Ossifying fibromas form a part of the spectrum of fibro-osseous lesions of the jaws. They are rare, benign, nonodontogenic tumors that are commonly seen in the head, and neck region. Ossifying fibroma of the jaw is a benign fibro-osseous lesion that is a part of larger family of fibro-osseous lesions that includes - juvenile aggressive ossifying fibroma, psammomatous ossifying fibroma, extragnathic ossifying fibroma of the skull.Patients generally present with a history of painless expansion of a tooth bearing portion of the mandible, whereas the lesions of the maxilla are less common. Benign fibro-osseous of the maxilla constitutes a varied group of lesions with a common histologic characteristic: The substitution of normal bone by tissue composed of collagen and fibroblasts with variable amounts of mineralized substance that may be bone, cementum or both.In the present case, we hereby report a 35-year-old male patient who presented with painless swelling over middle one third of face - left side since 8 months. Patient had no significant medical history in the previous past (history of trauma 6 years earlier). Panoramic radiography revealed rounded mixed type of image over left side of posterior maxilla in relation to 23, 24, 25, 26 region, respectively. An incisional biopsy was carried out which yielded a definitive diagnosis of ossifying fibroma of the maxilla. Management of the lesion was carried out by taking into account the benign nature, growth pattern, and behavior of the lesion clinically and radio graphically with regular and periodic follow-up postoperatively.

Historically, ossifying fibroma has been referred to as fibro osteomas, osteofibroma benign fibro-osseous lesion. In 1872, Menzel [1] first described the known as ossifying fibroma, but it was Montgomery [2] whom in 1927 coined the term ossifying fibroma.

It is a rare, benign primary bone tumor that occurs most commonly in the lower jaw. Fibro-osseous lesions constitute a rare type of pathology classified as benign tumors of nonodontogenic lineage that affect the craniofacial area. [3] Ossifying fibroma is characterized by the replacement of normal bone by fibrous tissue and varying amount of newly formed bone or cementum like material or both. [4]

It is usually presented as a painless, slow growing, expansile intra bony lesion, which is believed to be confined to the jaws and craniofacial complex. Lesions with fibrous and osseous components include:

Fibro-osseous lesion other than fibrous dysplasia seems to arise from the periodontal membrane. [6] Ossifying fibroma is commonly seen between third and fourth decade of life. More frequently in women than in men (4:1). [7] Clinically these tumors manifest as slow growing intrabony mass that is normally well delimited and asymptomatic though over time the lesion may become large enough to cause facial deformation. [8]

According to the classification proposed by Waldrom in 1993 fibro-osseous lesions are divided into - fibrous dysplasia, ossifying fibroma, Desmoplastic fibroma. [9]

One remarkable finding is the large size of the maxillary tumors at the time of diagnosis, probably attributable to the large amount of available space in the maxillary sinus into which they could expand similar to our case study. Though the growth was sufficiently large, patient did not present with significant clinical symptoms as it was extending over the sinus region. [10]

Case Report

A 35-year-old male patient reported to the author's clinic with the chief complaint of swelling over the left side of cheek region since 8 months. To begin with it was nonprogressive and asymptomatic. General physical examination did not reveal any abnormalities. Patient reported having suffered trauma in that same area years ago.

Extraorally lesion presented as fullness with ill-defined borders over middle 1/3 rd of face on the left side. Overlying skin was normal in appearance [Figure 1].

Overlying swelling was nontender; hard in consistency associated with grade I mobility in relation to 24, 25, and 26. He had good oral hygiene status with no clinically detectable dental caries and periodontal problems. Vitality of 24, 25, and 26 was unresponsive and fine needle aspiration cytology was negative. Based on clinical presentation a provisional impression of a benign neoplasm was considered.

Incisional biopsy was carried out and definitive diagnosis of ossifying fibroma was reached. Complete surgical removal of the lesion (enucleation) was carried out under local anesthesia with conscious sedation. After raising a mucoperiosteal flap in toto removal of the lesion, extraction of 24, 25, 26, gross debridement was done and the bone bed was subjected to curettage followed by wound closure [Figure 6].

The excised specimen was stored in 10% formalin and subjected to histopathological evaluation. The postoperative course was favorable and 2 years later the patient reported no discomfort in that zone with satisfactory wound healing [Figure 7].

Although there are persistent differences in terms of classification and diagnosis of fibro-osseous lesions in craniofacial area, there is consensus on the common characteristics of these lesions. All of them show the replacement of normal bone tissue with fibroblasts and collagen fiber tissue, with varying quantities of mineralized substances. [9]

Today there is a general agreement that ossifying fibroma and cemento-ossifying fibroma are a separate entity from fibrous dysplasia and an effort to simplify the classification, reflecting the view of Waldron that both of these lesions fall within the spectrum of same disease entity (this is supported by the fact that the periodontal ligament is able to elaborate both bone and cementum, acting on the alveolar periosteum as well as attachment of the tooth. [11]

In 1971, the WHO classified four types of cementum containing lesions:

The WHO classifies ossifying fibroma as a fibro-osseous neoplasm included among the nonodontogenic tumors derived from the mesenchymal blast cells of periodontal ligament, with a potential to form fibrous tissue, cement and bone, or a combination of such elements. [14],[15]

Pathogenesis

Although the underlying cause is not known, there have been reports of past trauma in the areas of the lesion. The same was evidenced in our case report. This point to trauma as a possible triggering factor in some presentations of the lesion, postulating the latter as representing a connective tissue reaction rather than a genuine neoplasm. [16],[17]

Suggested hypothesis include:

According to KEMPSOH [18] - bone deposition and resorption occurring on the same spicules of the bone. It was postulated that ossifying fibroma resulted from excessive resorption of bone with fibrous repair of the defect.

Trauma induced stimulation of progenitor cells has been suggested by WEING.

A comprehensive review of the lesion was published by EVERSOLE in their report of 64 cases. Ossifying fibromas occur over a wide age range. The majority of cases are encountered in the third and fourth decades of life (same evidenced in the present case report, as the age was 35 years). Clinically, the lesion presents as painless, slow growing intrabony mass of the jaw where displacement of teeth may be the only early clinical feature. [7]

Differential diagnosis

The set of entities in differential diagnosis appearing as benign neoplasm include:

Due to good delimitation of the tumor, surgical removal and curettage is the treatment of choice. In case of very large lesions with important tissue ablation, the challenge is to replace the affected tissue. [21] The circumscribed nature of the lesion permits the local enucleation or curettage of smaller lesions. [7]

The treatment of ossifying fibroma generally has been grouped into:

Conservative enucleation.

Curettage.

Radical surgery.

The recommended treatment of choice of the ossifying fibroma is excision. The entire tumor should be removed including a rim of normal tissues. Management should be individualized and case specific, depending on the size, location, benign nature and growth behavior of the lesion accordingly. [22]

In the present case, we selected conservative treatment that is, enucleation of the lesion with thorough debridement, curettage of the bone bed was done to promote good healing of the defect. Patient was followed-up regularly and after 2 years postoperatively patient had sound bone regeneration devoid of recurrence at the operated site.

According to MacDonald-Jankowski [23] has indicated enucleation or curettage as the first treatment option affords a recurrence rate of 0-28%; if relapse is identified in the course of follow-up, conservative resection is obligate. Recurrence rates of aggressive forms of ossifying fibromas are about 30-38%.

Conclusion

Despite the many years of dedicated study by numerous investigators, the concepts and parameters of fibro-osseous diseases are still in flux. Ossifying fibromas are comparatively rare benign tumors of maxillofacial region. Being capsulated it can be easily differentiated from other dysplastic conditions of the bone.

Treatment of ossifying fibroma should always be conservative excision of the well circumscribed without resection of the adjacent structures unless involved by the lesion; this should be accompanied with extraction of involved teeth and primary closure of wound respectively with timely follow-up.

From a clinical stand point, the fibro-osseous lesions may vary from the extensive and cosmetically or functionally disturbing lesions detected only during a routine radiographic examination. Any discussion of such lesions must begin with the observation that the term fibro-osseous is largely descriptive, nosologically limited, and diagnostically nonspecific.